Anti-rust compositions

ABSTRACT

Anti-Rust Compositions: A. LUBRICATING OIL BASE B. A NAPHTHOL SELECTED FROM 1-NAPHTHOL, 2-NAPHTHOL, AND 1NITROSO-2-NAPHTHOL C. A METAL SULFONATE SELECTED FROM NEUTRAL ALKALI METAL SULFONATE, NEUTRAL ALKALINE EARTH METAL SULFONATE, NEUTRAL ZINC SULFONATE, OVERBASED ALKALI METAL SULFONATE, OVERBASED ALKALINE EARTH METAL SULFONATE, AND OVERBASED ZINC SULFONATE D. A DETERGENT SELECTED FROM ALKENYL SUCCINIMIDES, ALKENYLSUCCINIC ESTERS, ALKYLLACTONE AMIDES, ALKYLLACTAM AMIDES, AND Mannich bases.

Unite States tet 1191 Heiba et al.

[ ANTI-RUST COMPOSITIONS [75] Inventors: El-Ahmadi Ibrahim Heiba,

Princeton; Albert Lloyd Williams, Hopewell Twp., both of NJ.

[73] Assignee: Mobil Oil Corporation, New York,

[22] Filed: May 30, 1974 [21] Appl. No.: 474,495

[52] U.S. Cl 252/33.4; 252/51.5 R; 252/51.5 A; 252/52 R; 252/565; 252/74; 252/75; 252/389 R; 252/392; 252/396 [51] Int. Cl..... ClOm 1/40; ClOm 1/32;C10m l/20 [58] Field of Search 252/33.4, 52 R, 51.5 R, 252/56 S, 51.5 A, 75, 389 R, 392, 396, 74

[56] References Cited UNITED STATES PATENTS 2,691,634 10/1954 Benoit 252/56 R 2,833,717 5/1958 Whitacre 252/33.4 2,968,620 l/l96l Cafcas et a1. 252/334 3,235,510 2/1966 Collings et a1. 252/33.4 3,492,234 l/l97() Andress et a1. 252/52 R 3,554,945 1/1971 Andress et a1. 252/52 R [57] ABSTRACT Anti-Rust Compositions:

a. lubricating oil base b. a naphthol selected from l-naphthol, 2-naphthol,

and l-nitroso-2-naphthol c. a metal sulfonate selected from neutral alkali metal sulfonate, neutral alkaline earth metal sulfonate, neutral zinc sulfonate, overbased alkali metal sulfonate, overbased alkaline earth metal sulfonate, and overbased zinc sulfonate d. a detergent selected from alkenyl succinimides, alkenylsuceinic esters, alkyllactone amides, alkyllactam amides, and Mannich bases.

13 Claims, No Drawings ANTI-RUST COMPOSITIONS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to lubricating and hydraulic oil compositions having improved rust inhibition and in particular to oil compositions containing a mixture of oil additives.

2. Prior Art of the Invention A desirable function of lubricating oils used in automotive, marine railroad or other engines is the ability to prevent rust of the metal parts. Often moisture, usually condensed from the atmosphere, is present in engines and other machinery, causing rust. Certain oil additives have been used as rust preventors or inhibitors, particularly the metal sulfonates, both neutral and overbased complex sulfonates. Reference to U.S. Pat. Nos. 2,616,911, 2,721,843, 2,739,124, 2,856,360, 2,861,951, 3,658,703, 3,155,616 and other patents of that classification indicate typical preparation of the overbased metal sulfonates.

U.S. Pat. No. 3,634,241 discloses sulfonate salts of alkenylsuccinimides. U.S. Pat. No. 3,219,666 discloses preparation of dispersants from alkenylsuccinic anhydrides and amines and the use thereof in oils along with basic sulfonates promoted by alcohols or phenols. As indicated in U.S. Pat. No. 3,488,284, preferred promoters are alcohols which do not contain a benzenoid ring.

U.S. Pat. Nos. 2,691,634, 3,492,234 and 3,554,945 disclose oil compositions containing naphthols or polyhydroxy naphthalenes as either flow additives or antioxidants.

SUMMARY OF THE INVENTION It has now been discovered that a lubricating or hydraulic oil composition containing in admixture a lnaphthol or Z-naphthol or their nitroso-substituted counterparts and a Group ll metal sulfonate possesses excellent anti-rust properties. In addition, the presence in the said oil composition ofa long-chain hydrocarbylsubstituted condensation product, useful as a detergent, of either an alkyl substituted lactam or lactone amide or an alkenylsuccinimide or alkenylsuccinic ester of an alkyl-substituted Mannich base further improves the rust inhibiting characteristic.

DESCRIPTION OF SPECIFIC EMBODIMENTS This invention contemplates the use of lubricating oil or hydraulic oil compositions having excellent rust ratings. The oil compositions are useful for such purposes as gear oils, turbine oils, hydraulic oils and greases and the like. Any hydrocarbon oil, either synthetic hydrocarbon or petroleum-based oil and ester oils may be used.

One component of the composition is a l-naphthol or 2-naphthol or the nitroso derivative thereof. Alkylsubstituted naphthols or phenols do not exhibit the performance provided by the aforesaid compounds.

The second component is the metal sulfonate. These organosulfonate additives are well known in the art. Generally they are Group II metal salts, such as barium, strontium, calcium, magnesium and zinc. Alkali metal sulfonates are also useful in this invention. Neutral sulfonates are readily prepared by reacting a metal oxide or hydroxide with the sulfonic acid. Methods of increasing the metal content to produce overbased sulfonates include treating the reaction mixture (containing excess metal oxide or hydroxide) with carbon dioxide. Carbonate-sulfonate metal complexes are formed. (U.S. Pat. Nos. 2,956,018, 3,027,325, 3,036,971 and 3,158,572 show these and other methods of preparing these sulfonate complexes). The preferred sulfonic acid has the formula or alkylbenzene sulfonates, wherein R represents one or more alkyl groups. R may contain from 8 to 50 carbon atoms, preferably 8 to 30. Wax benzene sulfonic acids, octadecyl sulfonic acid, and mixed C to C alkylbenzene sulfonic acids are preferred. The metal content of the resulting salts may contain over 200% excess metal (as in U.S. Pat. No. 3,436,347). The specific manner of preparing the neutral or overbased metal sulfonates used herein is not within the scope of this invention.

The naphthol and sulfonate may be present in the oil composition at concentrations ranging from about 0.3% to 5% by weight of naphthol and from about 0.5% to about 10% by weight of sulfonate. This admixture of these additives provide a synergistic response in the rust rating tests for oils.

The additional component which may also be present if desired may be at least one of the following:

1. alkenylsuccinimides 2. alkenylsuccinic esters 3. alkyllactone or alkyllactam amides 4. reaction product of alkylphenol, an aldehyde and an amine, termed Mannich base. These products have known detergent properties. Their utility in this invention is desirable, in part, because of the long-chain alkyl or alkenyl groups attached to the molecule. These hydrocarbyl groups contain from 15 to 300 carbon atoms. Preparation of such products is known in the art.

U.S. Pat. No. 3,172,892 describes a procedure for preparing alkenylsuccinicimides from the alkenylsuccinic anhydride and ethylene polyamines. Mono-imides and bis-imides may be prepared by providing sufficient anhydride to form either a single imido group at one H N- group or two imido groups at both H N groups of the polyamine. Tetraethylenepentamine is the preferred amine, although other amines of the formula H N(C H NH),,C H NI-I wherein n is 0 or an integer of l to 10, may be used.

Alkenylsuccinic esters are prepared by reacting the acid or anhydride with mono or polyhydric alcohols, of l to 4 hydroxy groups such as methanol, ethanol, butanol, octanol, decanol, dimethylpropanol, dimethylpropanediol, trimethylolpropane, trimethylolbutane, pentaerythrithol and dipentaerythritol. Typical preparation of these esters is disclosed in U.S. Pat. No. 3,381,022. The polyesters are the preferred class of additives.

The alkyllactone or alkyllactam amides are prepared by reacting an alkenylsuccinic anhydride, preferably obtained by reacting a polybutene or polyisobutylene with maleic anhydride, with an alcohol or by subjecting the anhydride to acid hydrolysis, illustrated as follows:

wherein R is the rest of the alkenyl group and either R" is hydrogen and x is l or R" is alkyl or aralkyl or alkylene or arylalkylene and x is from 1 to about 4. The catalyst is an acid such as hydrochloric acid when R" is hydrogen, or a sulfonic acid ion exchange resin. The resulting lactone acid or lactone ester is reacted with the ethylene polyamine to produce the lactone amide. If the reaction is carried out at sufficient temperature to replace the oxygen in the lactone ring, the lactam amide forms. Bis-lactam amides and even polymers may be so produced. Such compounds may have the formula and I uz-r R CH2 (in CH the dangling valences being hydrogen or a repeating segment.

The Mannich bases also useful in this invention are prepared by the procedure disclosed in US. Pat No. 3,368,972. The preferred bases are those of polypropylphenol having 20 to 300 carbon atoms in the alkyl chain, formaldehyde (or paraformaldehyde) and tetraethylene pentamine. Other mono or polyamines are suitable but TEPA provides desirable basicity for neutralization, and is readily available.

These non-ash-forming detergents are present in the oil compositions in concentrations of from about 0.5% to about by weight.

Other additives may be present in the lubricating oil compositions of this invention to provide antioxidant properties, viscosity index improvement and the like.

EXAMPLES The following examples are lubricant compositions subjected to rust rating tests and utilize different known additives.

cn-ca -c-oa" In each example, the oil is a Mid-continent sweet base oil of 5.38 cs viscosity at 210F. The identity of the additives is as follows:

1. Neutral Sulfonate a commercial neutral calcium alkylbenzene sulfonate, containing 1.45% by weight of calcium and 2% by weight of sulfur; molecular weight of the R50 group, about 700; total base number (TBN), 7 mg KOH per gram of material (product is designated as Lubrizol OS No. 16938, a product of The Lubrizol Corporation).

2. Succinic Ester a reaction product of polyisobutenylsuccinic anhydride of about 2300 mo- CH-CH j-nmc mmm c n x lecular weight and pentaerythritol.

3. Bis-imide a reaction product of about 2 moles of the polybutenylsuccinic anhydride of about 1000 molecular weight and one mole of tetraethylenepentamine.

4. Overbased Sulfonate a commercial overbased calcium alkylbenzene sulfonate, containing about 12% by weight of calcium and 1.6% by weight of sulfur; molecular weight of the RSO group is 385; TBN, 300 (product is designated as Lubrizol 690, a product of The Lubrizol Corporation).

Other additives used herein are designated by their chemical names.

The test procedure is a modification of ASTM D1748. In the present test, Oldsmobile steel push rod sections 4% inches long (halfa rod) are dipped into the test oil, allowed to drain and suspended in a humidity cabinet at 60C. for 22 hours, with redipping every 40 minutes. This procedure measures the relative ability of the various oil compositions to prevent rusting of steel under high humidity acidic conditions.

Duration of test 22 hours Air temperature 60C. Volume of cabinet 52 liters Rate of air to cabinet Rate of nitric oxide to 12.5 liters/hr.

cabinet 25 ml./hr Water level in cabinet 2 in. Frequency of dipping in oil 1.5 per hr.

The push rods are held inside the cabinet in an air-plusnitric oxide stream with complete immersion in test oil every 40 minutes for seconds. At the end of the test the rods are removed from the cabinet, washed in CRC solvent (40% ethylacetate, 30% methanol, 5% butylalcohol, 25% orthodichlobenzene) to remove any oil and examined for rust. The rating is similar to that of the Coordinating Research Councils rust rating on the scale of 1.0 to 10.0, as given in CRC Manual No. 7, 1.0 corresponding to heavy rust all over the specimen, 10.0 corresponding to a completely unblemished rod. A rating in this present test of 5.0 is a pass, above 5.0 is good to excellent, below 5.0 is failure.

These results show that at a total concentration of 6.5, the neutral sulfonate and the ester together provide almost no rust protection, as does either naphthol alone or with ester. The naphthol with the sulfonate has a passing rating. However, the same three components at individual concentrations below that previously used do provide unexpectedly higher ratings.

The same sulfonate and ester used in Tests Nos. 7 and 8 were tested at the same respective concentrations in formulations with other hydroxyaromatic compounds, such as alkylated naphthols, phenols, dihydroxyphenols and the like. All failed to meet the CRC standard rust rating of 5.0.

Several of the above hydroxy'aro'matic compounds, particularly the bisphenol of Test No. 15, are known anti-oxidants for oil compositions, yet they fail in this rust test.

Oil compositions containing the bis-imide also indicate synergism:

' Conc. Rust Test No. Oil Composition Wt.% Rating 1 Oil Alone 1.0 16 Neutral Sulfonate 2.5 1.0

Bis-imide 4.0 3 Z-Naphthol 2.0 l .O l 7 Z-Naphthol 0.5

Neutral Sulfonate 2.0 6.8 Bis-imide 3.5

Use of an overbased calcium sulfonate does not significantly improve the rust rating with the succinic alone. Again, the naphthol must be present:

The above series of tests show that naphthol and overbased sulfonate together provide acceptable rust protection. Test No. 19 resulted in a rust rating of 5.8 at a total concentration of only 1.5%. Although the succinic ester provided little additional rust protection to the sulfonate in Test No. 18, the rating of this combination increased to 9.7 with the presence of 2-naphthol in Test No. 20. The 1-nitroso-2-naphthol in Test No. 21 is not sufficiently soluble in oil to use alone as a rust preventive agent. However, with the sulfonate-ester combination, a very good rating was obtained.

The formulations of this invention are of particular interest in hydraulic oils. The likelihood of moisture in the oil system is ever-present and, thus, the danger of rust of metal parts is significant. The presence of naphthol and sulfonate in the formulation could provide the necessary protection. If the imide or ester detergent is also present, such results as achieved in Test N0. 20 could be imparted to a hydraulic oil formulation.

Having described our invention, we claim:

1. An oil composition comprising a lubricating oil medium and, in amount sufficient to provide rust inhibiting properties thereto, (1) a naphthol selected from the group consisting of l-naphthol, Z-naphthol and 1- nitroso-Z-naphthol and (2) a metal sulfonate selected from the group consisting of neutral alkali metal sulfonate, neutral alkaline earth metal sulfonate, neutral zinc sulfonate, overbased alkali metal sulfonate, overbased alkaline earth metal sulfonate, and overbased zinc sulfonate.

2. The composition of claim 1 wherein the metal sulfonate is a neutral sulfonate.

3. The composition of claim 1 wherein the metal sulfonate is an overbased sulfonate.

4. The composition of claim 1 wherein the metal is calcium.

5. The composition of claim 1 wherein there is also present in a detergent amount a long-chain hydrocarbyl-substituted organic condensation product having from 20 to 300 carbon atoms in the hydrocarbyl group, said product being selected from the group consisting of alkenylsuccinimides, alkenylsuccinic esters, alkyllactone amides, alkyllactam amides, and Mannich bases.

6. The composition of claim 5 wherein the said product is an ester of an alkenylsuccinic anhydride and an aliphatic alcohol having 1 to 4 hydroxy groups.

7. The composition of claim 6 wherein the ester is a polyester of a polybutenylsuccinic anhydride and pentaerythritol.

8. The composition of claim 1 wherein at least 0.3% by weight is naphthol.

9. The composition of claim 5 wherein there is present at least 0.5% by weight of naphthol, at least 1% by weight of an overbased calcium sulfonate and at least 3.5% by weight of a polybutenylsuccinic ester of pentaerythritol.

10. The composition of claim 5 wherein the said product is an alkenylsuccinimide of an ethylenepolyamine having the formula H N(C H NH),,H, wherein n is from 1 to l0.

hydraulic oil and turbine oil. 

1.AN OIL COMPOSITION COMPRISING A LUBRICATING OIL MEDIUM AND, IN AMOUNT SUFFICIENT TO PROVIDE RUST INHIBITING PROPERTIES THERETO, (1)A NAPHTHOL SELECTED FROM THE GROUP CONSISTING OF 1- NAPHTHOL, 2-NAPHTHOL AND 1-NITROSO-2-NAPHTHOL AND (2) A METAL SULFONATE SELECTED FROM THE GROUP CONSISTING OF BETURAL ALKALI METAL SULFONETE, NEUTRAL ALKALINE EARTH METAL SULFONATE, NEUTRAL ZINC SULFONATE, OVERBASED AKALI METAL SULFONATE, OVERBASED ALKALINE EARTH METAL SULFONATE, AND OVERBASED ZINC SULFONATE.
 2. The composition of claim 1 wherein the metal sulfonate is a neutral sulfonate.
 3. The composition of claim 1 wherein the metal sulfonate is an overbased sulfonate.
 4. The composition of claim 1 wherein the metal is calcium.
 5. THE COMPOSITION OF CLAIM 1 WHEREIN TERE IS ALSO PRESENT IN A DETERGENT AMOUNT A LONG-CHAIN HYDROCARBYL-SUBTITUTED ORGANIC CONDENSATION PRODUCT HAVING FROM 20 TO 300 CARBON ATOMS IN THE HYDROCARBYL GROUP, SAID PRODUCT BEING SELECTED FROM THE GROUP CONSISTING OF ALKENYLSUCCINIMIDES, ALKENYLSUCCINIC ESTERS, ALKYLLACTONE AMIDES, ALKYLLACTAM AIDES, AND MANNICH BASES.
 6. The composition of claim 5 wherein the said product is an ester of an alkenylsuccinic anhydride and an aliphatic alcohol having 1 to 4 hydroxy groups.
 7. The composition of claim 6 wherein the ester is a polyester of a polybutenylsuccinic anhydride and pentaerythritol.
 8. The composition of claim 1 wherein at least 0.3% by weight is naphthol.
 9. The composition of claim 5 wherein there is present at least 0.5% by weight of naphthol, at least 1% by weight of an overbased calcium sulfonate and at least 3.5% by weight of a polybutenylsuccinic ester of pentaerythritol.
 10. The composition of claim 5 wherein the said product is an alkenylsuccinimide of an ethylenepolyamine having the formula H2N(C2H4NH)n-H, wherein n is from 1 to
 10. 11. The composition of claim 10 wherein the alkenylsuccinimide is a bis(polybutenylsuccinimide) of tetraethylenepentamine.
 12. The composition of claim 5 wherein the naphthol is 1-nitroso-2-naphthol and the sulfonate is an overbased calcium sulfonate.
 13. The composition of claim 1 wherein the lubricating oil medium is selected from the group consisting of hydraulic oil and turbine oil. 